This invention relates to a pipe assembly conducting a hot fluid, for example, a hot gas generated from a nuclear reactor.
In general, a pipe assembly conducting a hot fluid should be high in heat-insulating property and high in resistance against the thermal expansion of the inner metal pipe directly contacting the hot fluid. A conventional pipe assembly conducting a hot fluid is prepared by disposing refractory blocks such as bricks on the outer surface of the inner metal pipe, with a filler like mortar used for filling the clearances between the refractory blocks. However, a pipe assembly of this type is not satisfactory in heat-insulating property and durability. In particular, the filler tends to be broken because of the thermal expansion of the inner metal pipe. Quite naturally, the breakage of the filler should be avoided particularly where the pipe assembly is used for conducting a hot gas generated from a nuclear reactor.